We use a modem to connect a PC to the Internet through a public telephone line. They're two basic types of modems for desktop PC. They are the internal and the external modem.

The internal modem is a circuit board that is inserted in an expansion slot within a PC. It doesn't need a extra supply of power and doesn't take up space on desktop. Another advantage is that the internal modem cost less than the external modem; However, it is more difficult to install and to configure the internal modem. The speed at which the internal modem can transmit and receive is from 300 bps to 56k bps.

The external modem is a device that connects a PC through the serial port. An adapter is required to provide power. It's easier to install the external modem and not necessary to open the PC's cover. There is almost nothing to configure. Unlike the internal modem, the external modem has eight indicator lights that indicate exactly what it's doing. This is an important feature of the external modem. There is no speed difference between the internal and the external modem.

Both the internal modem and the external modem have the same functions and comply with the same industry standards.